1. Field of the Invention
The present invention relates to a medical instrument, and particularly, relates to a medical instrument which includes: an elongated insertion section to be inserted into a subject, having a distal end portion provided with a treatment instrument projection port through which a treatment instrument is projected; and an active bending section.
2. Description of the Related Art
An endoscope is used for observation of organs in a body cavity by inserting its elongated insertion section into the body cavity, and to perform various treatments using a treatment instrument which is inserted through a channel in the treatment instrument. In the industrial field also, an endoscope can be used for observations and examinations of damage or corrosion in boiler, turbine, engine, or chemical plants by inserting its elongated insertion section in the inner portions of these units.
Such an endoscope has a bendable bending section connected to a distal end portion of the elongated insertion section. In order to bend the bending section of an endoscope, a so-called manually driven endoscope is widely used, and in using the endoscope, an operator operates a bending operation lever which is provided to an operation section thereof so as to directly pull or relax a wire that is inserted through the insertion section and is fixed to the bending section.
To the contrary, an electric endoscope is disclosed in Japanese Patent Application Laid-Open Publication No. 61-92650, the endoscope having an active bending section for pulling or relaxing a wire which is fixed to a bending section of the endoscope by a driving section such as a motor. In the electric endoscope, an operator operates a bending input section such as a joystick to input a direction for bending, or a speed for bending of an active bending section as an amount of bending for example. Then, the motor which is controlled based on the input amount of bending pulls/relaxes the bending operation wire, so that the bending section is operated to bend.
In the manually driven type endoscope, an operator variously changes the bending operation of the bending section without knowing. For example, while inserting the distal end portion of the endoscope to a target site in a body, or while observing a wide range for examination, an operator increases a speed for bending to achieve a quick insertion, and also considerably bends the portion, but while observing and performing various treatments using the treatment instrument inserted through a channel after the distal end portion is inserted to a target site, the operator decreases the bending speed, and also slightly and carefully bends the portion. Also, an operator variously changes the bending operation of the bending section without knowing, depending on the type of a treatment instrument inserted through the channel. For example, when the treatment instrument is a forceps, an operator quickly moves its bending section, and when the treatment instrument is an electric scalpel, an operator decreases the speed and carefully moves the scalpel. That is, the bending section of an endoscope is used in completely different manners for insertion and for treatment. In this way, in the case of a manually driven-type endoscope, an operator significantly changes the way to use the bending section, in other words, the bending operation, for insertion and for treatment, so as to ensure the accuracy of the treatment, and also reduce the time required for a treatment and the burden to a patient.
In the case of electric endoscope also, an operator can change the bending speed by an operation input section such as a joystick. For example, in many cases, a larger inclination of a joystick causes a higher bending speed, and a slighter inclination causes a lower bending speed.